Yarn and method of making the same



Nov. 25, 1969 H. A. WALTERS 3,479,811

YARN AND METHOD OF MAKING THE SAME Filed Nov. 29, 1967 INVENTOR. Hora/0 4. W0 fleas nited States Patent 3,479,811 YARN AND METHOD 0r MAKING THE SAME Harold A. Walters, Beaverton, Mich, assignor to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed Nov. 29, 1967, Ser. No. 686,656 Int. Cl. D02g 3/22, 3/36; 132% 7/20 US. Cl. 57-153 12 Claims ABSTRACT OF THE DISCLOSURE Expandable microspheres are incorporated in a thread or yarn, subsequently heated to expand the microspheres and bulk the yarn. Bulking of the yarn after weaving or sewing provides tightly woven fabric or locked-in sewing thread.

This invention relates to treated yarn and a method, and more particularly relates to the incorporation of expandable microspheres into textile yarns.

The bulking of yarns has been accomplished by various means. Fabrics have been impregnated with expanded and expandable microspheres. However, such impregnation is usually carried out after the weaving or other intertwining process has been completed. Oftentimes, it IS desirable that the yarns expand after being formed or incorporated into an article to provide what appears to be a tighter weave or otherwise secure and/ or interlock the yarn with its adjacent neighbors.

It would be advantageous if there were available a method and yarn which would form apparently relatively densely woven fabric without the necessity of weaving tightly.

It would also be beneficial if there were available a sewing thread which could be subsequently expanded after installation in a desired location.

It would also be desirable if there were avialable an improved method for bulking yarn.

These benefits and other advantages in accordance with the present invention are achieved by providing a yarn of a fibrous nature, impregnating the yarn with a dispersion containing expandable synthetic resinous microspheres which comprise a synthetic thermoplastic resinous wall and a distinct and separate liquid phase of a volatile expanding agent, subsequently disposing said microspheres within the yarn in a desired location, heating the yarn to a temperature sufiicient to cause expansion of the microspheres, thereby causing bulking of the yarn.

Also contemplated within the scope of the present invention is a yarn of a fibrous nature containing therein a plurality of synthetic resinous thermoplastic microspheres having a distinct and separate liquid phase therein, the microspheres being capable of expanding on heating to a diameter substantially greater than the original diameter of the microsphere.

Further features and advantages of the present invention will become more apparent from the following specication when taken in connection with the drawing wherein:

FIGURE 1 is a schematic enlarged representation of a yarn in accordance with the present invention.

FIGURE 2 is a schematic cross-sectional representation of a fabricated article in accordance with the invention.

FIGURE 3 is a schematic representation of a yarn having expanded microspheres therein.

In FIGURE 1 there is depicted a schematic representation of a yarn of a fibrous nature generally indicated by the reference numeral 10. The yarn 10 comprises a plurality of fibers or filaments 11 disposed in generally parallel adjacent relationship. A plurality of expandable syn- 3,479,811 Patented Nov. 25, 1969 'ice thetic resinous microspheres 12 are disposed in interstitial spaces 13 between the adjacent filaments 11. The microspheres 12 consist of a synthetic resinous thermoplastic hollow spherical shell containing a distinct and separate liquid phase of a blowing agent therein. Such expandable microspheres are well known in the art and are set forth in Belgian Patent 641,711.

In FIGURE 2 there is represented a schematic sectional view of a fabric 20 prepared from yarn in accordance with the present invention. The fabric 20 comprises a first set of generally parallel yarns 21 and a second set of generally parallel yarns 22 disposed generally in angular relationship to the set 21 and interwoven therewith. The dotted lines indicate the configuration of the yarns 21 and 22 after being subjected to heat sufiicient to cause the microspheres contained within the filaments to expand.

In FIGURE 3 there is depicted a portion of an expanded yarn 25 which has been removed from a fabric structure after expansion of the yarn. The yarn 25 has unexpanded or locking portions 26 and 27 arising from mechanical restraint during microspheres expansion.

A wide variety of yarns may be employed in the practice of the present invention such as threads, cordage and the like prepared from cotton, silk, jute, sisal, hemp, linen and wool, as Well as synthetics such as vinylidene chloride polymer multifilament, nylon, polyacrylonitrile, polyethylene, terephthalate, polypropylene, polyvinyl chloride, viscose rayon and blends of natural fibers, synthetic fibers as well as blends of natural and synthetic fibers.

It is critical to the present invention that the yarn define accessible void spaces between the fibers or filaments and be capable of expansion; that is, separation of the fibers or filaments sufiicient to admit microspheres into the interstitial spaces. Most yarns meet these requirements. A few yarns have been treated with a coating or bonding material or by heat treatment to a degree sufiicient to prevent such expansion. A wide variety of expandable microspheres are known and described in Belgian Patent 641,711. Generally, the particular nature of the microsphere is not critical. However, it is generally desirable to select a heat expanding microsphere having a composition which permits expansion at a temperature appropriate to the yarn employed; that is, one should not employ a microsphere which expands at a temperature above a temperature at which the strength or quality of the yarn or thread being treated is impaired such as by de-orientation, shrinkage, embrittlement or the like.

Oftentimes it is desirable to apply the microspheres to the yarn in combination with an adhesive material which promotes adhesion of the microspheres in the unexpanded form and subsequently in the expanded form to the surface of the fibers or filaments making up the yarn. Such adhesives or binders are well known and some are described in Belgian Patent 641,711. If, due to the particular nature of the yarn, an adhesive or binder is required, it is essential that one that is employed be inert to the expandable microspheres; that is, the binder must not destroy the structure of the microsphere. Typical binders or adhesives which are employed are synthetic resinous latexes or colloidal dispersions which are film forming at temperatures at which the microspheres initially start to expand to temperatures well below ambient temperatures. The particular adhesive employed will depend on the yarn, the characteristics required in the finished yarn such as friction, stiffness and the like. Selection of such adhesives is well within the skill of the art. Film forming synthetic resinous dispersions, such as polymers of styrene and butadiene such as a polymer of 70 parts by weight styrene and 30 parts by weight butadiene, are eminently satisfactory for many purposes, as are film forming vinylidene chlo-' ride polymers in aqueous colloidal dispersion such as a polymer of 85 weight percent vinylidene chloride and 15 weight percent acrylonitrile; water-soluble synthetic resins such as polyacrylic acid; water or alcohol soluble resins such as hydroxypropyl methyl cellulose; thermosetting resins such as the epoxy resins and the like. Beneficially in many instances, the addition of an adhesive may be omitted particularly with sized synthetic resinous yarns which have outer surfaces coated with a resin which softens or becomes tacky at temperatures of about 100 to 125 C., such as a polymer of 72 weight percent ethylene and 28 weight percent acrylic acid.

Beneficially in the practice of the present invention, the expandable synthetic resinous microspheres may be incorporated Within the yarn by a variety of techniques including immersion of the yarn in a liquid suspension of expandable microspheres. Beneficially, a tow of such yarns is impregnated by spraying, dipping, rolling, brushing or other conventional liquid-applying means. One particularly advantageous method of preparing a yarn impregnated with expandable microspheres is to pass the yarn to be coated through a bath and subsequently doctor the excess material therefrom by means of a perforated rubber diaphragm.

By way of further illustration, a polymerization re actor equipped with an agitator is charged with 100 parts of deionized water and 15 parts of a 30 weight percent colloidal silica dispersion in water. The colloidal silica dispersion is 30 weight percent solids and available under the trade name of Ludox HS. To this mixture is added 2.5 parts of a 10 weight percent aqueous solution of a copolymer prepared from diethanol amine and adipic acid in equimolar proportions by carrying out a condensation: reaction to give a product having a viscosity of about 100 centipoises at 25 C. One part of a solution containing 2.5 weight percent potassium dichromate is added. The pH of the aqueous solution is adjusted to 4 with hydrochloric acid. A methyl methacrylate and acrylonitrile mixture is utilized as the monomer in a proportion of 4:1, respectively. An oil phase mixture is prepared utilizing 100 parts of the foregoing monomer mixture and containing 35 weight percent neopentane and 0.1 part of benzoyl peroxide as a catalyst. The oil phase mixture is added to the water phase with violent agitation supplied by a blade rotating at a speed of about 10,000 revolutions per minute. The reactor is immediately sealed and a portion of the contents sampled to determine the particle size. The droplets appear to have diameters of from about 2 to about 10 microns. After the initial dispersion, the reaction mixture is maintained at a temperature of about 80 C. for a period of 24 hours. At the end of this period, the temperature is lowered and the reaction mixture has the appearance of a white, milky liquid similar to a chalkwhite milk. A portion of the mixture is filtered to remove the beads and the beads subsequently dried in an air oven at a temperature of about 30 C. A portion of the dried beads are heated in an air oven at a temperature of 150 C. for about 3 minutes. Upon heating, the beads show a marked increase in volume. Microscpoic examination of the beads prior to foaming indicates beads having diameters of from about 2 to about 10 microns and having dispersed therein a distinct spherical zone which appears to contain liquid and a small Vapor space. The beads which have been heated are examined micro scopically and are found to have diameters of from about 2 to times the diamter of the original bead and a relatively thin, transparent wall and a gaseous center, i.e., a monocell. The remaining portion of the chalk-White material is filtered to provide a wet'filter cake containing about 29.6 Weight percent expandable microspheres. A coating mixture is prepared by admixing 81.1 parts by weight of a polymer latex of 60 weight percent styrene and 40 weight percent butadiene which is 49.3 weight percent solids, 2.7 parts by weight of a 25 weight percent aqueous solution of sodium dodecyl diphenyl oxide disulfonate, 207 parts by weight of water and 16.2 parts by weight of a 5 weight percent aqueous solution of a thickening agent commercially available under the trade designation of Acrysol GS. The coating solution is then applied to a plurality of yarns by immersing the yarns and doctoring olf excess coating material by drawing through an opening formed by perforating a thin rubber diaphragm with a needle. The coated yarn is air-dried at a temperature of about 60 C. Portions of the thread are subsequently formed by heating in an air oven at 135 C. The yarns employed and the results are as follows:

YARN 1 A No. 40 cotton thread is coated with a dry coating weight of 0.0846 gram per 10 feet and after expansion increases to about twice its original diameter.

YARN 2 A No. 50 cotton thread is coated with a dry coating weight of 0.0534 gram per 10 feet and after expansion increases to about twice its original diameter.

YARN 3 A sized silk thread manufactured by Belding and Corticelli is coated with a dry coating weight of 0.1336 gram per 10 feet and after expansion increases to about 50 percent of its original diameter with a substantial increase in thickness.

YARN 4 A nylon thread designated as Coats and Clark Taslan textured nylon thread is coated with a dry coating weight of 0.042 gram per 10 feet and after expansion of the microspheres shows localized areas of individual fibers curled and standing out from the body of the thread.

YARN 5 Coats and Clark No. 333 wool yarn requires a dry coating weight of 0.0289 gram per 10 feet and on expansion increases its diameter about 2.5 times.

Other foamable microsphere coating compositions are prepared as follows:

COMPOSITION A 106.6 parts by weight of expandable microspheres having a polymer shell which is a polymer of weight percent vinylidene chloride and 20 weight percent acrylo nitrile containing 35 weight percent neopentane based on the combined weight of polymer and neopentane, the filter cake containing 25 weight percent Water, parts by weight of water, 40 parts by weight of a 60-40 copolymer of styrene and butadiene latex, 50 Weight percent solids, 78.3 parts by weight of a 5 weight percent solution of the sodium salt of polyacrylic acid.

COMPOSITION C Ninety parts by weight of a wet filter cake of expandable microspheres having a polymer shell of 60 weight percent styrene and 40 weight percent acrylonitrile copolymer containing 35 weight percent neopentane based on the combined weight of the polymer and neopentane and 25 parts by weight water, 103 parts by weight water, 60.4 parts by weight of an aqueous latex, 50 percent solids of a polymer of 85 weight percent vinyl chloride, weight percent butyl acrylate and 5 weight percent acylic acid, 10 parts by weight of a 10 weight percent solution of hydroxyethyl cellulose.

COMPOSITION D Ninety-four parts by weight of a wet filter cake of expandable microspheres having a polymer shell of 80 weight percent methyl methacrylate and weight percent methyl acrylate and weight percent neopentane based on the combined weight of the neopentane and the copolymer and 25 weight percent water, 100 parts by weight water, parts by weight of a weight percent solids latex of a polymer of weight percent styrene and 40 weight percent butadiene, 78.3 parts by weight of a 5 Weight percent aqueous solution of the sodium salt of polyacrylic acid.

Similar beneficial and advantageous results are obtained when cotton, silk, wool and nylon threads are coated With compositions A, B, C, and D. Use of coated or impregnated threads prepared in accordance with the present invention is susceptible of being embodied with 1y heated to a temperature sufficient to cause expansion, substantially eliminates the need for knotting or tying of the thread at either end thereof, as after heating the thread to cause expansion, it is difiicult to remove the thread from a woven fabric. Similar advantages are achieved when expandable thread of the present invention is employed for attaching buttons. Fabric woven from the expandable yarns prepared in accordance with the present invention and heat treated to expand the microspheres provides a dense-appearing fabric much tighter than original weave and with significant antiravelling properties.

As is apparent from the foregoing specification, the present invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention.

What is claimed is:

1. A method of providing a bulked yarn of a fibrous nature comprising providing a yarn,

impregnating the yarn with a dispersion containing synthetic resinous microspheres, the microspheres comprising a synthetic thermoplastic resinous wall and a distinct and separate liquid phase of a volatile expanding agent which is a non-solvent for the resinous wall, subsequently disposing said microspheres within the yarn in a desired location,

heating the yarn to a temperature sufiicient to cause expansion of the microspheres, thereby causing bulking of the yarn.

2. The method of claim 1 wherein the microspheres are disposed within the yarn by dispersion from a liquid suspension of microspheres.

3. The method of claim 2 including the step of incorporating an adhesive material within the microsphere dispersion.

4. The method of claim 3 including the step of removing the liquid of the dispersion from the yarn prior to heating of the yarn.

5. The method of claim 1 including the step of intertwining the yarn with a plurality of yarns prior to the expansion thereof.

6. The method of claim 5 wherein the intertwining of the yarn is accomplished by weaving.

7. An improved textile yarn of a generally parallel fibrous nature, the yarn containing dispersed therethrough a plurality of synthetic resinous thermoplastic microspheres having a distinct and separate liquid phase therein, the microspheres being capable of expanding on heating to a diameter substantially greater than the original diameter of the microspheres and thereby bulking the yarn.

8. The filament of claim 7 intertwined with a plurality of like yarns.

9. The filament of claim 8 wherein the yarn is cotton.

10. The yarn of claim 8 wherein the yarn is silk.

11. The yarn of claim 8 wherein the yarn is nylon.

12. The yarn of claim 8 including an adhesive binding the microspheres to the yarn.

References Cited UNITED STATES PATENTS 2,744,291 5/1956 Stastny et al. 264-53 2,815,559 12/1957 Robinson 57164 XR 2,940,871 6/1960 Smith-Johannsen 117-138.8 3,100,926 8/1963 Richmond 28--75 3,154,604 10/1964 McMillan 264-53 XR 3,359,130 12/1967 Goldman 264-53 XR 3,372,215 3/1968 Muirhead et al. 264-53 MERVIN STEIN, Primary Examiner WERNER H. SCHROEDER, Assistant Examiner US. Cl. X.R. 

